The cuneate fasciculus, also known as the fasciculus cuneatus (plural: fasciculi cuneati) or column of Burdach, represents the lateral portion of the dorsal columns and carries input from between and including C1 and T6 1.
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Function
The cuneate fasciculus is responsible for transmitting vibration, conscious proprioception, and fine (discriminative) touch sensations from the upper body 1.
Gross anatomy
Peripheral connections
First-order neurones from peripheral receptors enter the spinal cord via the posterior roots, and unlike first-order neurones from the spinothalamic tract, do not synapse in the posterior posterior grey horn of the cord 1. Thus, these first-order neurones form the cuneate fasciculus of the dorsal columns if input was from between and including C1 and T6 1. If input is from T7 or below, the gracile fasciculus is formed instead, which is discussed separately.
Course
Unlike fibres of the spinothalamic tract, these first-order neurones in the cuneate fasciculus continue to ascend without decussation 1. This ipsilateral ascension continues until the medulla oblongata of the brainstem 1. Fibres of this tract are somatotopically organised for their entire course 1.
Upon reaching the cuneate nucleus of the caudal medulla oblongata these first-order neurones terminate and synapse with second-order neurones 1. These second-order neurones then decussate to the contralateral side, known as the internal arcuate fibres during this decussation 1. These decussated neurones continue to ascend as part of the medial lemniscus where they terminate in the ventral posterior nucleus of the thalamus 1. Here, they synapse with third-order neurones 1. It is these third-order neurones that finally project to the primary somatosensory area on the ipsilateral side of the cerebral cortex 1.
Related pathology
- intramedullary spinal tumour
- spinal cord injury
- Brown-Séquard syndrome
- transverse myelitis
- multiple sclerosis
- subacute combined degeneration of the cord
- nitrous oxide toxicity
- copper deficiency myeloneuropathy
- neurosyphilis (tabes dorsalis)
- HIV vacuolar myelopathy
History and etymology
Named after Karl Friedrich Burdach (1776-1847), German anatomist 1
See also
- gracile fasciculus (or column of Goll)